有色蔬菜农药多残留检测样品预处理方法研究

以韭菜、油菜、菠菜和胡萝卜为试材,在样品均质前添加石墨粉并采用SPE固相萃取方法进行提取液净化处理,分析其脱色效果,并对样品中72种农药的回收率进行测定,探讨有色蔬菜农药多残留GC-MS检测中的样品预处理方法。颜色较浅样品提取液净化时,用300mg石墨柱与PSA柱串联,可以有效地排除样品提取液中色素的干扰,使94%以上农药的回收率介于60%～120%之间。颜色较深样品除进行上述处理外,在样品均质前添加少量石墨粉,不仅可以获得理想的脱色效果,而且待测农药的吸附损失也较少,90%以上农药的添加回收率在60%～120%范围内,可以达到理想的检测效果。     

液相色谱法自制净化柱测定饲料中5种黄曲霉毒素

通过用自制净化柱净化,利用高效液相色谱仪对饲料中的黄曲霉毒素B1、B2、G1、G2、M1同时进行检测,样品经体积分数为84%的乙腈溶液提取,提取液通过自制净化柱净化、浓缩,三氟乙酸(TFA)柱前衍生,C18色谱柱分离,荧光检测器检测,外标法定量。5种黄曲霉毒素经过衍生后线性良好,对添加黄曲霉饲料样品进行加标回收,回收率在85%~102%,效果良好。     

同位素稀释-气相色谱/高分辨质谱法测定食品中的指示性毒杀芬

目的建立食品样品中P26,P50,P62等三大指示性毒杀芬的检测分析方法,为进一步开展常规监测提供技术平台和基础数据。方法食品样品使用索式提取系统(Soxtec)提取,提取液依次由30%酸性硅胶柱和氧化铝柱净化,利用同位素稀释-高分辨气相色谱/高分辨双聚焦磁式质谱联用(ID-HRGC/HRMS)技术对三种指示性毒杀芬单体P26,P50,P62进行定量定性分析。结果本研究所建成的检测方法相对标准偏差(RSD)小于25%,回收率可以达到40%~120%;P26,P50,P62的方法检测限分别为0.08、0.02、0.06 pg/g;方法性能达到开展食品样品中毒杀芬检测技术的要求。结论该方法可以对食品样品中毒杀芬进行检测,检测效率高,结果准确可靠。     

高效液相色谱法同时测定月饼中的苯甲酸、山梨酸和糖精钠

目的:建立一种前处理简单、方便、灵敏度高、重现性好的月饼样品中苯甲酸、山梨酸和糖精钠的检测方法.方法:采用反相色谱法同时测定月饼样品中的苯甲酸、山梨酸和糖精钠含量.氢氧化钠溶液和硫酸锌作为沉淀剂,Symmetry C1s柱(250mm × 4.6mm,5μm)液相色谱柱分离,乙酸盐缓冲溶液-甲醇(体积比90:10)作为流动相,二级管阵列检测器进行检测.结果:检测波长选择230nm:样品加标回收率为92.4%～103.0%;苯甲酸、山梨酸和糖精钠检测限都为0.5mg/kg.结论:该方法可用于月饼中防腐剂的检测.     

同位素稀释-气相色谱/高分辨质谱法测定食品中的指示性毒杀芬指示性毒杀芬

目的 建立食品样品中P26, P50, P62等三大指示性毒杀芬的检测分析方法,为进一步开展常规监测提供技术平台和基础数据。方法 食品样品使用索式提取系统(Soxtec)提取, 提取液依次由30%酸性硅胶柱和氧化铝柱净化, 利用同位素稀释-高分辨气相色谱/高分辨双聚焦磁式质谱联用(ID-HRGC/HRMS)技术对三种指示性毒杀芬单体P26, P50, P62进行定量定性分析。结果 本研究所建成的检测方法相对标准偏差(RSD)小于25%, 回收率可以达到40%~120%; P26, P50, P62的方法检测限分别为0.08、0.02、0.06 pg/g; 方法性能达到开展食品样品中毒杀芬检测技术的要求。结论 该方法可以对食品样品中毒杀芬进行检测, 检测效率高, 结果准确可靠。     

食醋中有机磷农药残留的测定

用气相色谱法(GC)分析测定并采用凝胶色谱净化(GPC)系统预处理,建立了食醋中有机磷残留量的检测方法。样品用乙腈提取,经凝胶渗透色谱柱净化,再经中等极性的毛细管色谱柱DB-1701P(30m×0.25mm×0.25μm)分离,气相色谱火焰光度检测器(FPD)检测。有机磷在食醋样品中的残留量检测的检出限为0.0040～0.050mg/kg。在样品中添加29种农药混合标准溶液,平均回收率为72.4%～120.8%,相对标准偏差为0.7%～14.5%(n=3),可满足食醋样品中有机磷农残的测定。     

玉米制品中黄曲霉毒素的柱前和柱后衍生方法对比

玉米制品中黄曲霉毒素测定的2种衍生化方法(柱前衍生和柱后衍生)进行比较。样品经过Mycrosep ~(TM)226多功能净化柱净化,采用Waters Symmetry C18(4.6 mm×250 mm,5.0μm)色谱柱进行分离,荧光检测器检测。柱前衍生法:样品提取液经净化后,采用三氟乙酸进行衍生后测定。柱后碘衍生法:样品提取液经净化后,经高效液相色谱分离、柱后碘衍生,荧光检测器检测。结果表明:柱前衍生法,黄曲霉毒素G_1、B_1检出限为0.05μg/kg,黄曲霉毒素G_2、B_2检出限为0.015μg/kg,r0.999 1,回收率在75.4%~84.2%之间;柱后碘衍生法,黄曲霉毒素G_1、B_1检出限为0.08μg/kg,黄曲霉毒素G_2、B_2检出限为0.015μg/kg,r0.999 2,回收率在75.2%~85.7%之间。2种衍生方法在线性范围、精密度、回收率等方面较相似,表明柱前衍生法和柱后碘衍生法均适用于玉米制品中的黄曲霉毒素检测。     

食醋中环苯丙-脯二肽快速检测方法研究

目的:建立食醋中环二肽的快速检测方法。方法:采用反相高效液相色谱法(RP-HPLC)对食醋中环二肽的检测方法进行研究。流动相为V超纯水∶V甲醇=40∶60;流速0.6mL/min,等梯度洗脱;检测波长215nm;色谱柱为ZorbaxSB-C18快速检测柱(600Bar,4.6mm×150mm,1.8μm),柱温45℃。结果:在此条件下环二肽线性良好(相关系数0.9996),精密度高(RSD<2.5%),其样品回收率98.63%～102.32%。结论:开发出一种重复性好,准确性高,简便、快捷的环二肽液相检测方法,可在5min内完成样品检测。     

高效液相色谱-ELSD法检测泡菜中三氯蔗糖的含量

针对泡菜产品,建立了一种快速、有效的三氯蔗糖检测方法。样品经乙醇超声提取,直接浓缩、复溶和过滤,滤液进高效液相色谱仪,C18柱分离,蒸发光散射检测器(ELSD)检测。样品加标回收率范围为88.3%~92.1%,RSD均小于5%。该法可用于泡菜中三氯蔗糖含量的检测。     

啤酒酿造原料中黄曲霉毒素B_1、玉米赤霉烯酮和赭曲霉毒素A同时检测分析方法研究

研究建立同时检测啤酒及酿造原料中黄曲霉毒素B1、玉米赤霉烯酮和赭曲霉毒素A的免疫亲和柱净化-柱后化学衍生-高效液相色谱方法。样品经过甲醇-水(80∶20,v/v)提取,通过免疫亲和柱进行富集和净化,采用Thermo BDS HYPERSIL C18色谱柱,以乙腈-2%乙酸(40∶60,v/v)为流动相,等度洗脱,柱后以0.5%碘溶液衍生、改变波长荧光检测。结果表明,黄曲霉毒素B1、玉米赤霉烯酮和赭曲霉毒素A检出限分别为0.05μg/kg(AFB1)、3.19μg/kg(ZEA)和0.22μg/kg(OTA),标准曲线的线性范围分别为0.2~10.0μg/L、10.0~1000.0μg/L和5.0~50.0μg/L;在大麦样品中加标回收率为90.0%~109.5%,相对标准偏差为2.18%~4.94%。被检37个样品的真菌毒素含量检测结果表明,正常贮存下的啤酒原料均未检测出真菌毒素,但在霉变大麦样品中可以检测出少量的真菌毒素。     

Textural Properties of Cold-set Gels Induced from Heat-denatured Whey Protein Isolates

A 9% whey protein (WP) isolate solution at pH 7.0 was heat-denatured at 80°C for 30 min. Size-exclusion HPLC showed that native WP formed soluble aggregates after heat-treatment. Additions of CaCl2 (10–40 mM), NaCl (50–400 mM) or glucono-delta-lactone (GDL, 0.4–2.0%, w/v) or hydrolysis by a protease from Bacillus licheniformis caused gelation of the denatured solution at 45°C. Textural parameters, hardness, adhesiveness, and cohesiveness of the gels so formed changed markedly with concentration of added salts or pH by added GDL. Maximum gel hardness occurred at 200 mM NaCl or pH 4.7. Increasing CaCl2 concentration continuously increased gel hardness. Generally, GDL-induced gels were harder than salt-induced gels, and much harder than the protease-induced gel.     

Occurrence of bisphenol-F-diglycidyl ether (BFDGE) in fish canned in oil

The levels of bisphenol-F-diglycidyl ether (BFDGE) were quantified as part of a European survey on the migration of residues of epoxy resins into oil from canned fish. The contents of BFDGE in cans, lids and fish collected from all 15 Member States of the European Union and Switzerland were analysed in 382 samples. Cans and lids were separately extracted with acetonitrile. The extraction from fish was carried out with hexane followed by re-extraction with acetonitrile. The analysis was performed by reverse phase HPL C with fluorescence detection. BFDGE could be detected in 12% of the fish, 24% of the cans and 18% of the lids. Only 3% of the fish contained BFDGE in concentrations considerably above 1mg/kg. In addition to the presented data, a comparison was made with the levels of BADGE (bisphenol-A-diglycidyl ether)analysed in the same products in the context of a previous study.     

Contribution of European research to risk analysis

The European Commission's, Quality of Life Research Programme, Key Action 1—Health, Food & Nutrition is mission-oriented and aims, amongst other things, at providing a healthy, safe and high-quality food supply leading to reinforced consumer confidence in the safety of European food. Its objectives also include the enhancing of the competitiveness of the European food supply. Key Action 1 is currently supporting a number of different types of European collaborative projects in the area of risk analysis. The objectives of these projects range from the development and validation of prevention strategies including the reduction of consumers risks; development and validation of new modelling approaches; harmonization of risk assessment principles, methodologies, and terminology; standardization of methods and systems used for the safety evaluation of transgenic food; providing of tools for the evaluation of human viral contamination of shellfish and quality control; new methodologies for assessing the potential of unintended effects of genetically modified (genetically modified) foods; development of a risk assessment model for Cryptosporidium parvum related to the food and water industries; to the development of a communication platform for genetically modified organism, producers, retailers, regulatory authorities and consumer groups to improve safety assessment procedures, risk management strategies and risk communication; development and validation of new methods for safety testing of transgenic food; evaluation of the safety and efficacy of iron supplementation in pregnant women; evaluation of the potential cancer-preventing activity of pro- and pre-biotic ('synbiotic') combinations in human volunteers. An overview of these projects is presented here.     

低温带皮菜籽粕微粉的不同粒级部分的功能特性

为研究低温带皮菜籽粕微粉的不同粒级部分的功能特性,以经低温脱脂的带皮菜籽粕为原料,经微粉碎后筛分成212~425μm、150~212μm和106~150μm的3个不同粒级的微粉样品,检测这些样品的吸水性、吸油性、乳化性和乳化稳定性、蛋白质体外消化率。结果表明:1 3个不同粒级的微粉样品之间的粗纤维含量存在显著差异,表明三者的结构组成成分有一定差异。23个微粉样品的乳化活性和乳化稳定性随粒度级别的减小而显著增加(P0.01)。33个微粉样品的蛋白质体外消化率随粒度级别的减小而显著增加(P0.01)。4不同粒级带皮菜籽粕微粉样品的吸水性与吸油性受其结构组成物质不同和粒度的双重影响,与粒度的相关性不明显。     

Microbiology of food taints

Fresh and processed foods are often spoilt by the presence of undesirable flavours and odours caused by microbial action. The aim of this paper is to review the current knowledge of microbiologically induced taints that occur in a wide range of foodstuffs, including meats, poultry, fish, crustaceans, milk, dairy products, fruits, vegetables, cereals and cereal products. Examples have been chosen where the compounds responsible for the taint have been identified and sufficient data obtained to demonstrate the involvement of microorganisms. However, in some cases the full identity of the causative organism may not have been elucidated. The types of microorganisms covered by this review include bacteria, fungi, yeasts, actinomycetes and cyanobacteria. Although cyanobacteria do not in general infect foods, their presence in aqueous systems and water supplies can lead to off-flavours in aquatic organisms and processed foodstuffs. Several examples of each of these processes are discussed. Wherever possible, the likely biosynthetic pathway used by the microorganism to produce the offending compound in a foodstuff is indicated.     

Analysis for organic residues from aids to polymerization used to make plastics intended for food contact

Polymers intended for food contact use have been analysed for organic residues which could be attributed to a range of substances employed as polymerization aids (e.g. initiators and catalysts). A wide range of polymers was extracted with solvents and the extracts analysed by gas chromatography-mass spectrometry (GC-MS). The overwhelming majority of substances identified were not derived from aids to polymerization but were oligomers, additives and adventitious contaminants. However, a small number of substances were identified as initiator residues. These included tetramethylsuccinonitrile (TMSN) which was observed in two polymers and it derived from recombination of two azobisisobutyronitrile (AIBN) initiator radicals. Methyl benzoate, benzoic acid, biphenyl and phenyl benzoate were detected in one poly(methyl methacrylate) sample and in two polyvinylchlorides and they are thought to be derived from benzoyl peroxide initiator. TMSN was subsequently targeted for analysis of poly-(methyl methacrylate) plastics using proton nuclear magnetic resonance spectrometry (¹     

Tests of potential functional barriers for laminated multilayer food packages. Part II: Medium molecular weight permeants

Experiments were performed to characterize the kinetics of the permeation of different medium molecular weight model permeants: bisphenol A, warfarin and anthracene, from liquid paraffin, through a surrogate potential functional barrier (25 microns-thick orientated polypropylene--OPP) into the food simulants olive oil and 3% (w/v) acetic acid. The characterization of permeation kinetics generally observed the permeation models previously reported to explain the experimental permeation results obtained for a low molecular weight group of model permeants. In general, the model permeants exhibited behaviour consistent with their relative molecular weights with respect to (a) the time taken to attain steady-state permeation into the food simulant in which they were more soluble, (b) their subsequent steady-state permeation rates, and (c) their partition between liquid paraffin and the OPP membrane.     

The development of reference materials for paralytic shellfish poisoning toxins in lyophilized mussel. I: Interlaboratory studies of methods of analysis

This paper describes the first part of a project undertaken to develop mussel reference materials for Paralytic Shellfish Poisoning (PSP) toxins. Two interlaboratory studies were undertaken to investigate the performance of the analytical methodology for several PSP toxins, in particular saxitoxin (STX) and decarbamoyl-saxitoxin (dc-STX) in lyophilized mussels, and to set criteria for the acceptance of results to be applied during the second part of the project: the certification exercise. In the first study, 18 laboratories were asked to measure STX and dc-STX in rehydrated lyophilized mussel material and to identify as many other PSP toxins as possible with a method of their choice. In the second interlaboratory study, 15 laboratories were additionally asked to determine quantitatively STX and dc-STX in rehydrated lyophilized mussel and in a saxitoxin-enriched mussel material. The first study revealed that three out of four postcolumn derivatization methods and one pre-column derivatization method sufficed in principle to determine STX and dc-STX. Most participants (13 of 18) obtained acceptable calibration curves and recoveries. Saxitoxin was hardly detected in the rehydrated lyophilized mussels and results obtained for dc-STX yielded a CV of 58% at a mass fraction of 1.86 mg/kg. Most participants (14 out of 18) identified gonyautoxin-5 (GTX-5) in a hydrolysed extract provided. The first study led to provisional criteria for linearity, recovery and separation. The second study revealed that 6 out of 15 laboratories were able to meet these criteria. Results obtained for dc-STX yielded a CV of 19% at a mass fraction of 3.49mg/kg. Results obtained for STX in the saxitoxin-enriched material yielded a CV of 19% at a mass fraction of 0.34mg/kg. Saxitoxin could not be detected in the PSP-positive material. Hydrolysis was useful to confirm the identity of GTX5 and provided indicative information about C1 and C2 toxins in the PSP-positive material. The methods used in the second interlaboratory study showed sufficiently consistent analysis results to undertake a certification exercise to assign certified values for STX and dc-STX in lyophilized mussel.     

The Ministry of Environmental Protection Issued "Feasible Technology Guidelines for Pollution Prevention and Control in Wood Pulping Process of the Paper Industry (Trial)" and Two Other Guiding Technical Documents

On December 27t＂, 2013, the Ministry of Environmenta Protection announced that, in order to implement ＂The Environmental Protection Law of the People＇ s Republic of China＂, improve the working system in environmenta protection technologies, and promote technologica advancement in pollution prevention, the Ministry of Environmental Protection sponsored the formulation of three guiding technical documents including ＂Feasible Technology Guidelines for Pollution Prevention and Contro n Wood Pulping Process of the Paper Industry （Trial）＂     

1~(st) Intelli-Tissue~ EcoEc Tissue Machine Supplied by PMP Group Successfully Put into Operation in China

正On April 29th,2014,Intelli-Tissue EcoEc tissue machine supplied by PMP Group successfully put into operation at Hebei Xuesong Paper Co.,Ltd.,this is the first such kind of paper machine of PMP Group in China.